1. Field of the Invention
The present invention relates to a digital test apparatus for testing a semiconductor device, and more particularly, to a digital test apparatus for converting an analog signal output from an analog semiconductor device into a DC (direct current) voltage and measuring the DC voltage.
2. Description of Related Art
Semiconductor devices can be classified as either analog or digital. An analog semiconductor device processes an analog signal and includes an operational amplifier and an audio output amplifier. A digital semiconductor device processes a digital signal and includes a small-scale integrated circuit (SSI), a large-scale integrated circuit (LSI) and a memory IC (integrated circuit).
Testers are used for evaluating the capabilities of the semiconductor devices. Analog and digital specific testers are used for analog semiconductor devices and digital semiconductor devices, respectively.
FIG. 1 shows an analog test apparatus 101 for testing a plurality of analog semiconductor devices 111,112. The analog test apparatus 101 includes an analog tester 131 and a plurality of switches 121˜124.
The analog tester 131 includes an AC digitizer 135 for converting analog signals AN1˜AN4 into digital signals. The analog tester 131 measures the digital signals to determine the capabilities of the analog semiconductor devices 111, 112.
The plurality of switches 121˜124 are sequentially turned on when testing the analog semiconductor devices 111,112 such that the analog signals AN1˜AN4 output from output pins P1˜P4 of the analog semiconductor devices 111, 112 are transmitted to the AC digitizer 135.
The AC digitizer 135 is needed to allow the analog tester 131 to test the analog semiconductor devices 111, 112. Including AC digitizers 135 in the analog tester 131 can become cost prohibitive.
In applications using a limited number of AC digitizers 135, the plurality of switches 121˜124 need to be used to simultaneously test the plurality of analog semiconductor devices 111, 112. The use of the plurality of switches 121˜124 increases the time needed for testing the analog semiconductor devices 111, 112, thus increasing time related expenses.
Also, if the frequencies of the analog signals AN1˜AN4 output from the analog semiconductor devices 111, 112 are high, the capability of the AC digitizer 135 needs to be improved, further increasing the cost for testing the analog semiconductor devices 111, 112.
Accordingly, to reduce the test cost, an inexpensive test apparatus is needed for simultaneously testing a plurality of analog semiconductor devices 111, 112 which output high frequency analog signals AN1.